id: security-tls-authentication title: Authentication using mTLS sidebar_label: “Authentication using mTLS” description: Get a comprehensive understanding of concepts and configuration methods of mTLS authentication in Pulsar.

import Tabs from '@theme/Tabs';
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mTLS authentication overview

Mutual TLS (mTLS) is a mutual authentication mechanism. Not only servers have keys and certs that the client uses to verify the identity of servers, clients also have keys and certs that the server uses to verify the identity of clients.

The following figure illustrates how Pulsar processes mTLS authentication between clients and servers.

Pulsar mTLS authentication process

Enable mTLS authentication on brokers

To configure brokers to authenticate clients using mTLS, add the following parameters to the conf/broker.conf. If you use a standalone Pulsar, you need to add these parameters to the conf/standalone.conf file:

# enable authentication
authenticationEnabled=true
# set mTLS authentication provider
authenticationProviders=org.apache.pulsar.broker.authentication.AuthenticationProviderTls

# configure TLS for client to connect brokers
brokerClientTlsEnabled=true
brokerClientTrustCertsFilePath=/path/to/ca.cert.pem
brokerClientAuthenticationPlugin=org.apache.pulsar.client.impl.auth.AuthenticationTls
brokerClientAuthenticationParameters={"tlsCertFile":"/path/to/broker_client.cert.pem","tlsKeyFile":"/path/to/broker_client.key-pk8.pem"}

# configure TLS ports
brokerServicePortTls=6651
webServicePortTls=8081

# configure CA certificate
tlsTrustCertsFilePath=/path/to/ca.cert.pem
# configure server certificate
tlsCertificateFilePath=/path/to/server.cert.pem
# configure server's private key
tlsKeyFilePath=/path/to/server.key-pk8.pem

# enable mTLS
tlsRequireTrustedClientCertOnConnect=true
tlsAllowInsecureConnection=false

# Tls cert refresh duration in seconds (set 0 to check on every new connection)
tlsCertRefreshCheckDurationSec=300

Enable mTLS authentication on proxies

To configure proxies to authenticate clients using mTLS, add the following parameters to the conf/proxy.conf file.

# enable authentication
authenticationEnabled=true
# set mTLS authentication provider
authenticationProviders=org.apache.pulsar.broker.authentication.AuthenticationProviderTls

# configure TLS for client to connect proxies
tlsEnabledWithBroker=true
brokerClientTrustCertsFilePath=/path/to/ca.cert.pem
brokerClientAuthenticationPlugin=org.apache.pulsar.client.impl.auth.AuthenticationTls
brokerClientAuthenticationParameters={"tlsCertFile":"/path/to/proxy.cert.pem","tlsKeyFile":"/path/to/proxy.key-pk8.pem"}

# configure TLS ports
brokerServicePortTls=6651
webServicePortTls=8081

# configure CA certificate
tlsTrustCertsFilePath=/path/to/ca.cert.pem
# configure server certificate
tlsCertificateFilePath=/path/to/server.cert.pem
# configure server's private key
tlsKeyFilePath=/path/to/server.key-pk8.pem

# enable mTLS
tlsRequireTrustedClientCertOnConnect=true
tlsAllowInsecureConnection=false

Configure mTLS authentication in Pulsar clients

When using mTLS authentication, clients connect via TLS transport. You need to configure clients to use https:// and the 8443 port for the web service URL, use pulsar+ssl:// and the 6651 port for the broker service URL.

<Tabs groupId="lang-choice"
  defaultValue="Java"
  values={[{"label":"Java","value":"Java"},{"label":"Python","value":"Python"},{"label":"C++","value":"C++"},{"label":"Node.js","value":"Node.js"},{"label":"Go","value":"Go"},{"label":"C#","value":"C#"}]}>
<TabItem value="Java">

```java
import org.apache.pulsar.client.api.PulsarClient;

PulsarClient client = PulsarClient.builder()
    .serviceUrl("pulsar+ssl://broker.example.com:6651/")
    .tlsTrustCertsFilePath("/path/to/ca.cert.pem")
    .authentication("org.apache.pulsar.client.impl.auth.AuthenticationTls",
                    "tlsCertFile:/path/to/client.cert.pem,tlsKeyFile:/path/to/client.key-pk8.pem")
    .build();
```

</TabItem>
<TabItem value="Python">

```python
from pulsar import Client, AuthenticationTLS

auth = AuthenticationTLS("/path/to/client.cert.pem", "/path/to/client.key-pk8.pem")
client = Client("pulsar+ssl://broker.example.com:6651/",
                tls_trust_certs_file_path="/path/to/ca.cert.pem",
                tls_allow_insecure_connection=False,
				authentication=auth)
```

</TabItem>
<TabItem value="C++">

```cpp
#include <pulsar/Client.h>

pulsar::ClientConfiguration config;
config.setUseTls(true);
config.setTlsTrustCertsFilePath("/path/to/ca.cert.pem");
config.setTlsAllowInsecureConnection(false);

pulsar::AuthenticationPtr auth = pulsar::AuthTls::create("/path/to/client.cert.pem",
                                                         "/path/to/client.key-pk8.pem")
config.setAuth(auth);

pulsar::Client client("pulsar+ssl://broker.example.com:6651/", config);
```

</TabItem>
<TabItem value="Node.js">

```javascript
const Pulsar = require('pulsar-client');

(async () => {
  const auth = new Pulsar.AuthenticationTls({
    certificatePath: '/path/to/client.cert.pem',
    privateKeyPath: '/path/to/client.key-pk8.pem',
  });

  const client = new Pulsar.Client({
    serviceUrl: 'pulsar+ssl://broker.example.com:6651/',
    authentication: auth,
    tlsTrustCertsFilePath: '/path/to/ca.cert.pem',
  });
})();
```

</TabItem>
<TabItem value="Go">

```go
client, err := pulsar.NewClient(ClientOptions{
		URL:                   "pulsar+ssl://broker.example.com:6651/",
		TLSTrustCertsFilePath: "/path/to/ca.cert.pem",
		Authentication:        pulsar.NewAuthenticationTLS("/path/to/client.cert.pem", "/path/to/client.key-pk8.pem"),
	})
```

</TabItem>
<TabItem value="C#">

```csharp
var clientCertificate = new X509Certificate2("admin.pfx");
var client = PulsarClient.Builder()
                         .AuthenticateUsingClientCertificate(clientCertificate)
                         .Build();
```

</TabItem>
</Tabs>

Configure mTLS authentication in CLI tools

Command-line tools like pulsar-admin, pulsar-perf, and pulsar-client use the conf/client.conf config file in a Pulsar installation.

To use mTLS authentication with the CLI tools of Pulsar, you need to add the following parameters to the conf/client.conf file, alongside the configurations to enable mTLS encryption:

webServiceUrl=https://localhost:8081/
brokerServiceUrl=pulsar+ssl://localhost:6651/
authPlugin=org.apache.pulsar.client.impl.auth.AuthenticationTls
authParams=tlsCertFile:/path/to/admin.cert.pem,tlsKeyFile:/path/to/admin.key-pk8.pem

Configure mTLS authentication with KeyStore

Apache Pulsar supports TLS encryption and mTLS authentication between clients and Apache Pulsar service. By default, it uses PEM format file configuration.

To configure mTLS authentication with KeyStore, complete the following steps.

Step 1: Configure brokers

Configure the broker.conf file as follows.

# Configuration to enable authentication
authenticationEnabled=true
authenticationProviders=org.apache.pulsar.broker.authentication.AuthenticationProviderTls

# Enable KeyStore type
tlsEnabledWithKeyStore=true

# key store
tlsKeyStoreType=JKS
tlsKeyStore=/var/private/tls/broker.keystore.jks
tlsKeyStorePassword=brokerpw

# trust store
tlsTrustStoreType=JKS
tlsTrustStore=/var/private/tls/broker.truststore.jks
tlsTrustStorePassword=brokerpw

# internal client/admin-client config
brokerClientTlsEnabled=true
brokerClientTlsEnabledWithKeyStore=true
brokerClientTlsTrustStoreType=JKS
brokerClientTlsTrustStore=/var/private/tls/client.truststore.jks
brokerClientTlsTrustStorePassword=clientpw
# internal auth config
brokerClientAuthenticationPlugin=org.apache.pulsar.client.impl.auth.AuthenticationKeyStoreTls
brokerClientAuthenticationParameters={"keyStoreType":"JKS","keyStorePath":"/var/private/tls/client.keystore.jks","keyStorePassword":"clientpw"}

tlsRequireTrustedClientCertOnConnect=true
tlsAllowInsecureConnection=false

Step 2: Configure clients

Besides configuring TLS encryption, you need to configure the KeyStore, which contains a valid CN as client role, for clients.

For example:

  1. for Command-line tools like pulsar-admin, pulsar-perf, and pulsar-client, set the conf/client.conf file in a Pulsar installation.

    webServiceUrl=https://broker.example.com:8443/
brokerServiceUrl=pulsar+ssl://broker.example.com:6651/
useKeyStoreTls=true
tlsTrustStoreType=JKS
tlsTrustStorePath=/var/private/tls/client.truststore.jks
tlsTrustStorePassword=clientpw
authPlugin=org.apache.pulsar.client.impl.auth.AuthenticationKeyStoreTls
authParams={"keyStoreType":"JKS","keyStorePath":"/var/private/tls/client.keystore.jks","keyStorePassword":"clientpw"}

  2. for Java client

    import org.apache.pulsar.client.api.PulsarClient;

PulsarClient client = PulsarClient.builder()
    .serviceUrl("pulsar+ssl://broker.example.com:6651/")
    .useKeyStoreTls(true)
    .tlsTrustStorePath("/var/private/tls/client.truststore.jks")
    .tlsTrustStorePassword("clientpw")
    .allowTlsInsecureConnection(false)
    .enableTlsHostnameVerification(false)
    .authentication(
            "org.apache.pulsar.client.impl.auth.AuthenticationKeyStoreTls",
            "keyStoreType:JKS,keyStorePath:/var/private/tls/client.keystore.jks,keyStorePassword:clientpw")
    .build();

  3. for Java admin client

        PulsarAdmin amdin = PulsarAdmin.builder().serviceHttpUrl("https://broker.example.com:8443")
        .useKeyStoreTls(true)
        .tlsTrustStorePath("/var/private/tls/client.truststore.jks")
        .tlsTrustStorePassword("clientpw")
        .allowTlsInsecureConnection(false)
        .enableTlsHostnameVerification(false)
        .authentication(
               "org.apache.pulsar.client.impl.auth.AuthenticationKeyStoreTls",
               "keyStoreType:JKS,keyStorePath:/var/private/tls/client.keystore.jks,keyStorePassword:clientpw")
        .build();

:::note

Configure tlsTrustStorePath when you set useKeyStoreTls to true.

:::